Effect of strain on electrochemical performance of Janus MoSSe monolayer anode material for Li-ion batteries: First-principles study*

First-principles calculations are performed to investigate the effect of strain on the electrochemical performance of Janus MoSSe monolayer. The calculation focuses on the specific capacity, intercalation potential, electronic structure, and migration behavior of Li-ion under various strains by using the climbing-image nudged elastic band method. The result shows that the specific capacity is nearly unchanged under strain. But interestingly, the tensile strain can cause the intercalation potential and Li-ion migration energy barrier increase in MoSSe monolayer, whereas the compressive strain can lead to the intercalation potential and energy barrier decreasing. Thus, the rate performance of the MoSSe anode is improved. By analyzing the potential energy surface of MoSSe surface and equilibrium adsorption distance of Li-ion, we explain the physical origin of the change in the intercalation potential and migration energy barrier. The increase of MoSSe potential energy surface and the decrease of adsorption distance caused by tensile strain are the main reason that hinders Li-ion migration.